The starting point of this project is to study young people and adolescents, aiming to explore the correlation between non-suicidal behavior of young people and adolescents and the negative emotional expression of their parents and family communication. The purpose of this project is to investigate the non-suicidal self-injury behavior of teenagers aged 15-25 years by issuing questionnaires (sample size: 327 people). In order to find out whether there is any connection between family communication and non-suicidal self-injury behavior of young people and adolescents.

The incidence of non-suicidal self-injury（NSSI） among adolescents has obviously increased, which should attract the attention of the whole society. Their mental health problems will not only lead to personal pain and family burden, but also bring potential negative effects to future social development. Therefore, it is necessary to study the psychological problems of teenagers and their influencing factors. This study will conduct a case-control study from the perspective of family, and analyze the negative emotional expression and family communication style of parents of non-suicidal teenagers and their influence on non-suicidal self-injury behavior. This study is conducted in the form of scale, which will use the demographic information，the Family Emotional Expressivity Questionnaire（FEEQ）、the Parent-Adolescent Communication Scale（PACS）、the Childhood Trauma Questionnaire（CTQ）、the Parental Bongding Instrument（PBI）、the Adolescent parent-child relationship intimacy questionnaire and the Ottawa Self-injury Inventory（OSI）.

1.Case group: NSSI patient group:

Inclusion Criteria:

1. Patients who meet the diagnostic criteria in DSM-5 and are clinically diagnosed as NSSI;
2. Age range: 15-25 years old;
3. Clear consciousness, normal speech function, able to communicate in Chinese and reading chinese;

Exclusion Criteria:

1. Users with organic diseases and psychoactive substances;
2. NSSI； caused by autism, TIC disorder, mental retardation and other emotional instability and bad mood;
3. Religious self-injury or customary self-injury;
4. Patients with schizophrenia, schizoaffective disorder, alcohol dependence, organic mental disorder and other mental disorders have been previously diagnosed.

2.Control group 1: Non-NSSI patients

Inclusion criteria:

1. Psychiatric outpatients or inpatients can read and understand the contents of the questionnaire;
2. Patients who do not meet the diagnostic criteria in DSM-5 and are clinically diagnosed as NSSI.
3. Age range: 15-25 years old;
4. Patients and/or guardians can give informed consent and participate in this study.

Exclusion criteria:

1. Patients whose illness causes them unable to communicate or fill out questionnaires;
2. Non-serious mental diseases, such as schizophrenia and schizoaffective disorder.

3.Control group 2: Healthy group

Inclusion criteria

1. No mental illness;
2. Age range: 15-25 years old;
3. Clear consciousness, normal speech function, able to communicate in Chinese and reading chinese;
4. Patients and/or guardians can give informed consent and participate in this study.

Exclusion criteria

(1) Young people and adolescents who are unable to communicate or fill out questionnaires due to various organic reasons.

The group of adolescents and young adults diagnosed as NSSI, and the control group includes adolescents and young adults with other mental diseases other than NSSI, healthy adolescents and young adults.